1. Field of the Invention
The present invention relates to a light emitting device and a fabricating method thereof. More specifically, the present invention relates to a light emitting diode (LED), a package structure thereof and a fabricating method thereof.
2. Description of Related Art
An LED is a semiconductor device. A material of light-emitting chips in the LED is generally selected from group III-V chemical elements such as GaP, GaAs, GaN, and other compound semiconductors. The light emitting principle lies in converting electric energy into light. In other words, by applying currents to the compound semiconductors, and through the combinations of electrons and electron holes, redundant energy is released in forms of light, so that light emitting effects are achieved.
The structure of the LED usually comprises a substrate, two semiconductor layers, an active layer, which is the light emitting layer, disposed between the two semiconductor layers and two external electrodes. When a forward bias voltage is applied to the external electrodes, current flows through the semiconductor layers, and combinations of electrons and electron holes are formed in the active layer, so that the active layer emits light.
As light emitting efficiencies increase, the LED has gradually replaced conventional fluorescent lamps and incandescent bulbs in application, and the fabrication of the LED is gradually developing towards trends of high power and large area. However, in the prior art, since the design of the electrodes in the LED is not of ideal disposition, currents are not uniform when the LED is driven, leading to inferior light emitting efficiencies of the LED. This problem is especially manifest on the edges of the electrodes, and may cause the electrodes or the nearby semiconductor layers to be destroyed. In addition, since the electrodes are not transparent, for some kinds of LEDs, light emitted from the active layer may be blocked or absorbed by the electrodes, thereby affecting the light emitting efficiencies of the LEDs.